It has been estimated that 25% of the natural gas in the United States contains unacceptably high levels of the non-combustive contaminant nitrogen. Efforts to remove nitrogen from natural gas have included methane sorption and various techniques of cryogenic distillation such as liquification, turbocryogenic distillation, and "cold box" separation. All such efforts, though successful, have been relatively expensive and inefficient. There thus exists a need for a simple, efficient and low cost method of selectively removing nitrogen from natural gas. This need and others are met by the present invention, which is summarized and described in detail below.